It is often desired to provide a thin, wear-resistant coating on a base metal to protect the base metal in an abrasive environment. One such proposed hard coating is titanium diboride (U.S. Pat. No. 3,802,078).
A convenient technique for applying thin wear-resistant coatings is to sputter the hard material from a target onto the base metal. Sputtering is a well known technique whereby materials are dislodged from a target or cathode using an electrical glow discharge.
The use of hard materials such as titanium diboride in these targets has presented a problem in that hard materials are frequently brittle and may crack and fail under thermal stress. Conventional sputter targets may employ target material mechanically clamped in a holder, adhesively bonded to a backing plate, or soft-soldered to a copper backing plate. In use, these conventional targets have frequently failed due to thermal stresses in the sputterable material or a thermal expansion mismatch between the sputterable material and its backing plate. The sputtering operation would then be terminated for replacement of the prematurely failed target.